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One of the less well-documented, potentially modifiable stroke risk factor is the obstructive sleep apnea. Obstructive sleep apnea increases cardiovascular morbidity and mortality, including stroke risk. The article summarizes the pathophysiological factors in sleep apnea syndrome which can increase stroke risk.

Unlabelled: Overproduction of free radicals in ageing tissues induces nitro-oxidative stress, which has been implicated in the functional decline of the cardiovascular system at old age. Toxic oxidants like hydrogen peroxide or peroxynitrite damage proteins and DNA and activate several pathways causing tissue injury, including the poly(ADP-ribose) polymerase (PARP) pathway., Aim: First, we tested whether the inhibition of PARP can improve endothelial dysfunction induced by hydrogen peroxide in an in vitro model of vascular oxidative stress. In turn, our main aim was to investigate the effects of acute PARP inhibition and catalytic peroxynitrite decomposition on ageing-associated cardiac and endothelial dysfunction., Methods: In vascular reactivity measurements on isolated rat aortic rings, we investigated the endothelium-dependent and -independent vasorelaxation by using acetylcholine and sodium nitroprusside. Endothelial dysfunction was induced by hydrogen peroxide. In the treatment group, rings were preincubated with a PARP-inhibitor. In the in vivo rat model of ageing-associated cardiovascular dysfunction, young and ageing rats were treated with a single dose of PARP-inhibitor, or with the peroxynitrite decomposition catalyst FP15. Using a pressure-conductance catheter, left ventricular pressure-volume analysis was performed to study cardiac function. Endothelium-dependent and -independent relaxation of aortic rings were investigated. Immunohistochemical analysis was performed to study the changes on the cellular and tissue level., Results: In our in vitro model, hydrogen peroxide caused a dose-dependent impairment of endothelium-dependent vasorelaxation of aortic rings which was significantly improved by PARP-inhibition. Ageing rats showed a marked reduction of cardiac function and loss of endothelium-dependent relaxant responsiveness of aortic rings. Both acute PARP-inhibition and FP15-treatment improved cardiac performance and endothelial function. Immunohistochemistry confirmed enhanced nitro-oxidative stress and PARP-activation in ageing rats, which were reversed in the treatment groups., Conclusions: Our results demonstrate the importance of endogenous peroxynitrite-overproduction and the activation of the PARP pathway in the age-related functional decline of the cardiovascular system. Catalytic peroxynitrite decomposition and PARP-inhibition may represent novel antioxidant therapeutic utilities to improve ageing-associated cardiovascular dysfunction.

The Authors present a female patient who suffered from alopecia areata caused by extreme solar abuse. Biological effects of ionizing radiation, the damages by free radicals and protection against oxidative damage are summarized. The main forms and risk factors of UV-radiation, skin damages by UV-light as well as the pathogenesis of the alopecia areata are reviewed.

The purpose of this review was to summarise what is known about the benign hepatic tumors, especially the role that free radicals play in the etiology and in the complications of these neoplasms. Nowadays benign liver tumors are considered as common entities. With the technical developments of radiology their diagnosis has become much easier, but still it is the major difficulty for the doctor to handle. There are different types of benign hepatic neoplasms: liver cyst, hemangioma, hepatocellular adenoma, focal nodular hyperplasia and there are also some rare tumor types. The relationship between hepatocellular adenoma and the use of oral contraceptives is well known. The oral contraceptives reduce the antioxidant capacity of the blood, this could be an explanation for the generation of these neoplasms. Benign liver tumors are also associated to thrombotic reactions. These neoplasms may require surgical treatment, so the oxidative stress is one of the main prognostic factors of the patients' survival.

Great importance has been attributed to antioxidants in the prevention and treatment of conditions associated with oxidative stress for many years. At the same time the antioxidants are free radicals themselves, and they can exert prooxidant activity depending on the concentration. They influence the cell redox homeostasis by their prooxidant and antioxidant activity as well. Drugs of chronic liver diseases should be considered, because free radicals are generated during the activity of the monooxygenase system, which affect the tissue oxidised status. Combined antioxidant treatment is more favourable compared with monotherapy, because antioxidants have scavenger-, compartment- and tissue-specificity and they regenerate each other directly, too. Beside their antioxidant property they may also directly regulate many important processes, e.g. cell cycle. We have some favourable results with regard combined antioxidant therapy of liver disease of different etiology.